The present invention relates to sprinkler heads used in automatic fire extinguishing systems for buildings and the like, and in particular relates to a locking ring which prevents removal of an escutcheon from the sprinkler heads.
Sprinkler heads have long been used in automatic fire extinguishing systems located in various buildings in order to controllably expel a fluid from the sprinkler head in an attempt to either suppress or extinguish the fire. The automatic sprinkler head itself can assume a variety of configurations and dimensions depending on the particular manufacturer and the environment in which it is to be used. One common type of automatic sprinkler head includes a metal base threadably connected to a pipe located in the ceiling and in fluid communication with a pressurized water source, or other fire extinguishing fluid. The base is integrally attached to and in fluid communication with the interior of the sprinkler head. The interior of the sprinkler head receives a deflector plate in operational connection with a seal biased in the closed position. The deflector plate is held within the interior of the body by a pair of outwardly biased pins depending from the bottom of the sprinkler head. These pins are held in an inwardly biased position by a thermally sensitive bridge member. During normal conditions, the thermally sensitive bridge member maintains the closed position of the seal and thereby prevents water or other fluid from being emitted into the designated area.
When the designated area reaches a preselected temperature indicative of a fire, the thermally sensitive bridge member will either melt or separate, causing the inwardly biased pins to move to the outward position. This in turn causes the deflector plate to be expelled from the interior of the sprinkler head and depend a preselected distance into the designated area. This action also results in the opening of the seal permitting pressurized water to enter the interior of the sprinkler body and be expelled therefrom. Once expelled, the trajectory of the water is altered by the deflector plate in an optimum manner to thereby extinguish or suppress a fire.
When an automatic sprinkler head is positioned within the ceiling, an annulus or gap is formed between the sprinkler head and the ceiling. This annulus is formed because in order to thread the base portion of the sprinkler head to the piping, the ceiling hole must be larger than the sprinkler head. This gap or annulus is both dangerous and unattractive. As a result, it is common practice to cover the annulus by using an escutcheon. An escutcheon is a cylindrical plate having a center bore. A set of threads is formed on the inner wall of the central bore. These threads are complementary to a set of external threads formed about the exterior of the bottom of the sprinkler head. Thus, the escutcheon is screwed onto the bottom portion of the sprinkler head thereby covering the annulus between the sprinkler head and the surrounding ceiling.
In most environments, an escutcheon which is simply threadably received by the exterior surface of the sprinkler head is satisfactory. However, automatic sprinkler heads are also used in environments wherein it is necessary to take precautions against tampering. In environments such as mental health facilities, prisons and correctional facilities, and some educational facilities, individuals may unscrew the escutcheon from the sprinkler head and thereafter damage the sprinkler head itself, or cause premature expulsion of water from the sprinkler head, thereby causing property damage. Moreover, once the escutcheon is removed, it is also possible for such individuals to be harmed by contact with electrical wiring often located in proximity to the piping which supplies water to the sprinkler head.
Therefore, there exists a need for a device which locks the escutcheon to the exterior surface of the sprinkler head and hence protects the same from damage caused by unauthorized removal.